Kidney stones are solid, pebble-like pieces of material that form in one or both kidneys from high levels of certain minerals in urine. They vary in size, from a grain of sand to larger than a pea. While some stones may pass unnoticed, others can cause discomfort and require medical attention. The duration a kidney stone remains in the body can vary widely, from days to several weeks, or even longer if intervention is needed. This variability depends on individual factors.
Factors Influencing How Long Stones Remain
The size of a kidney stone is a primary determinant of how quickly it passes. Smaller stones, typically under 4 millimeters, often pass on their own within one to two weeks. Stones between 4 and 6 millimeters may take longer, potentially around 45 days. Those larger than 6 millimeters can take up to 12 months or may not pass without assistance.
The stone’s location within the urinary tract also influences its passage time. Stones closer to the bladder in the ureter tend to pass more quickly than those higher up, nearer the kidney. If a stone causes a blockage in the urinary system, medical intervention may be necessary.
The composition of a kidney stone can also play a role, as different types, such as calcium oxalate or uric acid stones, possess distinct characteristics. Calcium oxalate stones are the most common. Adequate hydration is another important factor, as drinking sufficient water helps to dilute urine and facilitate stone movement. Individual anatomical variations within the urinary tract can further affect how easily a stone navigates the system.
Impact of a Stone Remaining in the Kidney
A kidney stone can cause various effects and symptoms. The most recognized symptom is intense, fluctuating pain, often called renal colic. This pain typically begins in the lower back and can radiate to the side or groin, occurring when the stone moves or obstructs urine flow.
A stone can block urine flow, leading to hydronephrosis, where urine backs up and causes the kidney to swell. Prolonged obstruction can lead to kidney damage. A blockage also increases the risk of urinary tract infections, which may present with fever and chills.
Irritation caused by the stone’s presence can result in blood in the urine, which may be visible or microscopic. While not all stones produce severe symptoms, especially if they are small and do not obstruct urine flow, complications can arise as long as the stone is present.
When Medical Intervention is Necessary
Certain symptoms indicate the need for prompt medical attention. These include unbearable pain that does not subside, fever and chills signaling an infection, persistent vomiting, or a complete inability to urinate. Such signs suggest a potential complication requiring immediate evaluation by a healthcare professional.
If a stone has not passed within several weeks, or if symptoms continue, medical assessment is important. Healthcare professionals can use various methods to assist passage or remove the stone. Medications like alpha-blockers can relax urinary tract muscles, making passage easier.
For stones that do not pass naturally, procedures include Extracorporeal Shock Wave Lithotripsy (ESWL), which uses shockwaves to break stones into smaller fragments. Ureteroscopy involves inserting a thin scope to remove or fragment the stone. Percutaneous Nephrolithotomy (PCNL) is typically reserved for larger stones and involves a small incision. The most suitable course of action is determined by a healthcare professional based on stone size, location, symptoms, and the individual’s overall health.
Strategies for Preventing New Stones
Preventing new kidney stones often involves adjusting daily habits and, in some cases, medical management. Drinking plenty of fluids, especially water, is a primary prevention strategy. Adequate hydration keeps urine diluted, reducing the concentration of stone-forming minerals.
Dietary modifications also play a significant role. Reducing sodium intake and limiting animal protein consumption can help. For those prone to calcium oxalate stones, managing oxalate-rich food intake may be beneficial. Ensuring adequate calcium from food sources, rather than supplements, is generally encouraged.
For those with recurrent stones or specific compositions, a doctor might recommend urine tests to identify the stone type. Based on results, medications can be prescribed to prevent future stone formation. Consulting a healthcare provider or dietitian is advisable for a personalized prevention plan.